// Released under MIT license
// Copyright (c) 2009-2010 Dominic Baggott
// Copyright (c) 2009-2010 Ash Berlin
// Copyright (c) 2011 Christoph Dorn <christoph@christophdorn.com> (http://www.christophdorn.com)

/*jshint browser:true, devel:true */
/* eslint-disable */
let expose = {};

(function () {
  /**
   *  class Markdown
   *
   *  Markdown processing in Javascript done right. We have very particular views
   *  on what constitutes 'right' which include:
   *
   *  - produces well-formed HTML (this means that em and strong nesting is
   *    important)
   *
   *  - has an intermediate representation to allow processing of parsed data (We
   *    in fact have two, both as [JsonML]: a markdown tree and an HTML tree).
   *
   *  - is easily extensible to add new dialects without having to rewrite the
   *    entire parsing mechanics
   *
   *  - has a good test suite
   *
   *  This implementation fulfills all of these (except that the test suite could
   *  do with expanding to automatically run all the fixtures from other Markdown
   *  implementations.)
   *
   *  ##### Intermediate Representation
   *
   *  *TODO* Talk about this :) Its JsonML, but document the node names we use.
   *
   *  [JsonML]: http://jsonml.org/ "JSON Markup Language"
   **/
  var Markdown = (expose.Markdown = function (dialect) {
    switch (typeof dialect) {
      case "undefined":
        this.dialect = Markdown.dialects.Gruber;
        break;
      case "object":
        this.dialect = dialect;
        break;
      default:
        if (dialect in Markdown.dialects) {
          this.dialect = Markdown.dialects[dialect];
        } else {
          throw new Error("Unknown Markdown dialect '" + String(dialect) + "'");
        }
        break;
    }
    this.em_state = [];
    this.strong_state = [];
    this.debug_indent = "";
  });

  /**
   *  parse( markdown, [dialect] ) -> JsonML
   *  - markdown (String): markdown string to parse
   *  - dialect (String | Dialect): the dialect to use, defaults to gruber
   *
   *  Parse `markdown` and return a markdown document as a Markdown.JsonML tree.
   **/
  expose.parse = function (source, dialect) {
    // dialect will default if undefined
    var md = new Markdown(dialect);
    return md.toTree(source);
  };

  /**
   *  toHTML( markdown, [dialect]  ) -> String
   *  toHTML( md_tree ) -> String
   *  - markdown (String): markdown string to parse
   *  - md_tree (Markdown.JsonML): parsed markdown tree
   *
   *  Take markdown (either as a string or as a JsonML tree) and run it through
   *  [[toHTMLTree]] then turn it into a well-formated HTML fragment.
   **/
  expose.toHTML = function toHTML(source, dialect, options) {
    var input = expose.toHTMLTree(source, dialect, options);

    return expose.renderJsonML(input);
  };

  /**
   *  toHTMLTree( markdown, [dialect] ) -> JsonML
   *  toHTMLTree( md_tree ) -> JsonML
   *  - markdown (String): markdown string to parse
   *  - dialect (String | Dialect): the dialect to use, defaults to gruber
   *  - md_tree (Markdown.JsonML): parsed markdown tree
   *
   *  Turn markdown into HTML, represented as a JsonML tree. If a string is given
   *  to this function, it is first parsed into a markdown tree by calling
   *  [[parse]].
   **/
  expose.toHTMLTree = function toHTMLTree(input, dialect, options) {
    // convert string input to an MD tree
    if (typeof input === "string") input = this.parse(input, dialect);

    // Now convert the MD tree to an HTML tree

    // remove references from the tree
    var attrs = extract_attr(input),
      refs = {};

    if (attrs && attrs.references) {
      refs = attrs.references;
    }

    var html = convert_tree_to_html(input, refs, options);
    merge_text_nodes(html);
    return html;
  };

  // For Spidermonkey based engines
  function mk_block_toSource() {
    return (
      "Markdown.mk_block( " +
      uneval(this.toString()) +
      ", " +
      uneval(this.trailing) +
      ", " +
      uneval(this.lineNumber) +
      " )"
    );
  }

  // node
  function mk_block_inspect() {
    var util = require("util");
    return (
      "Markdown.mk_block( " +
      util.inspect(this.toString()) +
      ", " +
      util.inspect(this.trailing) +
      ", " +
      util.inspect(this.lineNumber) +
      " )"
    );
  }

  var mk_block = (Markdown.mk_block = function (block, trail, line) {
    // Be helpful for default case in tests.
    if (arguments.length == 1) trail = "\n\n";

    var s = new String(block);
    s.trailing = trail;
    // To make it clear its not just a string
    s.inspect = mk_block_inspect;
    s.toSource = mk_block_toSource;

    if (line != undefined) s.lineNumber = line;

    return s;
  });

  function count_lines(str) {
    var n = 0,
      i = -1;
    while ((i = str.indexOf("\n", i + 1)) !== -1) n++;
    return n;
  }

  // Internal - split source into rough blocks
  Markdown.prototype.split_blocks = function splitBlocks(input, startLine) {
    input = input.replace(/(\r\n|\n|\r)/g, "\n");
    // [\s\S] matches _anything_ (newline or space)
    // [^] is equivalent but doesn't work in IEs.
    var re = /([\s\S]+?)($|\n#|\n(?:\s*\n|$)+)/g,
      blocks = [],
      m;

    var line_no = 1;

    if ((m = /^(\s*\n)/.exec(input)) != null) {
      // skip (but count) leading blank lines
      line_no += count_lines(m[0]);
      re.lastIndex = m[0].length;
    }

    while ((m = re.exec(input)) !== null) {
      if (m[2] == "\n#") {
        m[2] = "\n";
        re.lastIndex--;
      }
      blocks.push(mk_block(m[1], m[2], line_no));
      line_no += count_lines(m[0]);
    }

    return blocks;
  };

  /**
   *  Markdown#processBlock( block, next ) -> undefined | [ JsonML, ... ]
   *  - block (String): the block to process
   *  - next (Array): the following blocks
   *
   * Process `block` and return an array of JsonML nodes representing `block`.
   *
   * It does this by asking each block level function in the dialect to process
   * the block until one can. Succesful handling is indicated by returning an
   * array (with zero or more JsonML nodes), failure by a false value.
   *
   * Blocks handlers are responsible for calling [[Markdown#processInline]]
   * themselves as appropriate.
   *
   * If the blocks were split incorrectly or adjacent blocks need collapsing you
   * can adjust `next` in place using shift/splice etc.
   *
   * If any of this default behaviour is not right for the dialect, you can
   * define a `__call__` method on the dialect that will get invoked to handle
   * the block processing.
   */
  Markdown.prototype.processBlock = function processBlock(block, next) {
    var cbs = this.dialect.block,
      ord = cbs.__order__;

    if ("__call__" in cbs) {
      return cbs.__call__.call(this, block, next);
    }

    for (var i = 0; i < ord.length; i++) {
      //D:this.debug( "Testing", ord[i] );
      var res = cbs[ord[i]].call(this, block, next);
      if (res) {
        //D:this.debug("  matched");
        if (!isArray(res) || (res.length > 0 && !isArray(res[0]))) this.debug(ord[i], "didn't return a proper array");
        //D:this.debug( "" );
        return res;
      }
    }

    // Uhoh! no match! Should we throw an error?
    return [];
  };

  Markdown.prototype.processInline = function processInline(block) {
    return this.dialect.inline.__call__.call(this, String(block));
  };

  /**
   *  Markdown#toTree( source ) -> JsonML
   *  - source (String): markdown source to parse
   *
   *  Parse `source` into a JsonML tree representing the markdown document.
   **/
  // custom_tree means set this.tree to `custom_tree` and restore old value on return
  Markdown.prototype.toTree = function toTree(source, custom_root) {
    var blocks = source instanceof Array ? source : this.split_blocks(source);

    // Make tree a member variable so its easier to mess with in extensions
    var old_tree = this.tree;
    try {
      this.tree = custom_root || this.tree || ["markdown"];

      blocks: while (blocks.length) {
        var b = this.processBlock(blocks.shift(), blocks);

        // Reference blocks and the like won't return any content
        if (!b.length) continue blocks;

        this.tree.push.apply(this.tree, b);
      }
      return this.tree;
    } finally {
      if (custom_root) {
        this.tree = old_tree;
      }
    }
  };

  // Noop by default
  Markdown.prototype.debug = function () {
    var args = Array.prototype.slice.call(arguments);
    args.unshift(this.debug_indent);
    if (typeof print !== "undefined") print.apply(print, args);
    if (typeof console !== "undefined" && typeof console.log !== "undefined") console.log.apply(null, args);
  };

  Markdown.prototype.loop_re_over_block = function (re, block, cb) {
    // Dont use /g regexps with this
    var m,
      b = block.valueOf();

    while (b.length && (m = re.exec(b)) != null) {
      b = b.substr(m[0].length);
      cb.call(this, m);
    }
    return b;
  };

  /**
   * Markdown.dialects
   *
   * Namespace of built-in dialects.
   **/
  Markdown.dialects = {};

  /**
   * Markdown.dialects.Gruber
   *
   * The default dialect that follows the rules set out by John Gruber's
   * markdown.pl as closely as possible. Well actually we follow the behaviour of
   * that script which in some places is not exactly what the syntax web page
   * says.
   **/
  Markdown.dialects.Gruber = {
    block: {
      atxHeader: function atxHeader(block, next) {
        var m = block.match(/^(#{1,6})\s*(.*?)\s*#*\s*(?:\n|$)/);

        if (!m) return undefined;

        var header = ["header", { level: m[1].length }];
        Array.prototype.push.apply(header, this.processInline(m[2]));

        if (m[0].length < block.length)
          next.unshift(mk_block(block.substr(m[0].length), block.trailing, block.lineNumber + 2));

        return [header];
      },

      setextHeader: function setextHeader(block, next) {
        var m = block.match(/^(.*)\n([-=])\2\2+(?:\n|$)/);

        if (!m) return undefined;

        var level = m[2] === "=" ? 1 : 2;
        var header = ["header", { level: level }, m[1]];

        if (m[0].length < block.length)
          next.unshift(mk_block(block.substr(m[0].length), block.trailing, block.lineNumber + 2));

        return [header];
      },

      code: function code(block, next) {
        // |    Foo
        // |bar
        // should be a code block followed by a paragraph. Fun
        //
        // There might also be adjacent code block to merge.

        var ret = [],
          re = /^(?: {0,3}\t| {4})(.*)\n?/,
          lines;

        // 4 spaces + content
        if (!block.match(re)) return undefined;

        block_search: do {
          // Now pull out the rest of the lines
          var b = this.loop_re_over_block(re, block.valueOf(), function (m) {
            ret.push(m[1]);
          });

          if (b.length) {
            // Case alluded to in first comment. push it back on as a new block
            next.unshift(mk_block(b, block.trailing));
            break block_search;
          } else if (next.length) {
            // Check the next block - it might be code too
            if (!next[0].match(re)) break block_search;

            // Pull how how many blanks lines follow - minus two to account for .join
            ret.push(block.trailing.replace(/[^\n]/g, "").substring(2));

            block = next.shift();
          } else {
            break block_search;
          }
        } while (true);

        return [["code_block", ret.join("\n")]];
      },

      horizRule: function horizRule(block, next) {
        // this needs to find any hr in the block to handle abutting blocks
        var m = block.match(/^(?:([\s\S]*?)\n)?[ \t]*([-_*])(?:[ \t]*\2){2,}[ \t]*(?:\n([\s\S]*))?$/);

        if (!m) {
          return undefined;
        }

        var jsonml = [["hr"]];

        // if there's a leading abutting block, process it
        if (m[1]) {
          jsonml.unshift.apply(jsonml, this.processBlock(m[1], []));
        }

        // if there's a trailing abutting block, stick it into next
        if (m[3]) {
          next.unshift(mk_block(m[3]));
        }

        return jsonml;
      },

      // There are two types of lists. Tight and loose. Tight lists have no whitespace
      // between the items (and result in text just in the <li>) and loose lists,
      // which have an empty line between list items, resulting in (one or more)
      // paragraphs inside the <li>.
      //
      // There are all sorts weird edge cases about the original markdown.pl's
      // handling of lists:
      //
      // * Nested lists are supposed to be indented by four chars per level. But
      //   if they aren't, you can get a nested list by indenting by less than
      //   four so long as the indent doesn't match an indent of an existing list
      //   item in the 'nest stack'.
      //
      // * The type of the list (bullet or number) is controlled just by the
      //    first item at the indent. Subsequent changes are ignored unless they
      //    are for nested lists
      //
      lists: (function () {
        // Use a closure to hide a few variables.
        var any_list = "[*+-]|\\d+\\.",
          bullet_list = /[*+-]/,
          number_list = /\d+\./,
          // Capture leading indent as it matters for determining nested lists.
          is_list_re = new RegExp("^( {0,3})(" + any_list + ")[ \t]+"),
          indent_re = "(?: {0,3}\\t| {4})";

        // TODO: Cache this regexp for certain depths.
        // Create a regexp suitable for matching an li for a given stack depth
        function regex_for_depth(depth) {
          return new RegExp(
            // m[1] = indent, m[2] = list_type
            "(?:^(" +
              indent_re +
              "{0," +
              depth +
              "} {0,3})(" +
              any_list +
              ")\\s+)|" +
              // m[3] = cont
              "(^" +
              indent_re +
              "{0," +
              (depth - 1) +
              "}[ ]{0,4})"
          );
        }
        function expand_tab(input) {
          return input.replace(/ {0,3}\t/g, "    ");
        }

        // Add inline content `inline` to `li`. inline comes from processInline
        // so is an array of content
        function add(li, loose, inline, nl) {
          if (loose) {
            li.push(["para"].concat(inline));
            return;
          }
          // Hmmm, should this be any block level element or just paras?
          var add_to = li[li.length - 1] instanceof Array && li[li.length - 1][0] == "para" ? li[li.length - 1] : li;

          // If there is already some content in this list, add the new line in
          if (nl && li.length > 1) inline.unshift(nl);

          for (var i = 0; i < inline.length; i++) {
            var what = inline[i],
              is_str = typeof what == "string";
            if (is_str && add_to.length > 1 && typeof add_to[add_to.length - 1] == "string") {
              add_to[add_to.length - 1] += what;
            } else {
              add_to.push(what);
            }
          }
        }

        // contained means have an indent greater than the current one. On
        // *every* line in the block
        function get_contained_blocks(depth, blocks) {
          var re = new RegExp("^(" + indent_re + "{" + depth + "}.*?\\n?)*$"),
            replace = new RegExp("^" + indent_re + "{" + depth + "}", "gm"),
            ret = [];

          while (blocks.length > 0) {
            if (re.exec(blocks[0])) {
              var b = blocks.shift(),
                // Now remove that indent
                x = b.replace(replace, "");

              ret.push(mk_block(x, b.trailing, b.lineNumber));
            } else {
              break;
            }
          }
          return ret;
        }

        // passed to stack.forEach to turn list items up the stack into paras
        function paragraphify(s, i, stack) {
          var list = s.list;
          var last_li = list[list.length - 1];

          if (last_li[1] instanceof Array && last_li[1][0] == "para") {
            return;
          }
          if (i + 1 == stack.length) {
            // Last stack frame
            // Keep the same array, but replace the contents
            last_li.push(["para"].concat(last_li.splice(1, last_li.length - 1)));
          } else {
            var sublist = last_li.pop();
            last_li.push(["para"].concat(last_li.splice(1, last_li.length - 1)), sublist);
          }
        }

        // The matcher function
        return function (block, next) {
          var m = block.match(is_list_re);
          if (!m) return undefined;

          function make_list(m) {
            var list = bullet_list.exec(m[2]) ? ["bulletlist"] : ["numberlist"];

            stack.push({ list: list, indent: m[1] });
            return list;
          }

          var stack = [], // Stack of lists for nesting.
            list = make_list(m),
            last_li,
            loose = false,
            ret = [stack[0].list],
            i;

          // Loop to search over block looking for inner block elements and loose lists
          loose_search: while (true) {
            // Split into lines preserving new lines at end of line
            var lines = block.split(/(?=\n)/);

            // We have to grab all lines for a li and call processInline on them
            // once as there are some inline things that can span lines.
            var li_accumulate = "";

            // Loop over the lines in this block looking for tight lists.
            tight_search: for (var line_no = 0; line_no < lines.length; line_no++) {
              var nl = "",
                l = lines[line_no].replace(/^\n/, function (n) {
                  nl = n;
                  return "";
                });

              // TODO: really should cache this
              var line_re = regex_for_depth(stack.length);

              m = l.match(line_re);
              //print( "line:", uneval(l), "\nline match:", uneval(m) );

              // We have a list item
              if (m[1] !== undefined) {
                // Process the previous list item, if any
                if (li_accumulate.length) {
                  add(last_li, loose, this.processInline(li_accumulate), nl);
                  // Loose mode will have been dealt with. Reset it
                  loose = false;
                  li_accumulate = "";
                }

                m[1] = expand_tab(m[1]);
                var wanted_depth = Math.floor(m[1].length / 4) + 1;
                //print( "want:", wanted_depth, "stack:", stack.length);
                if (wanted_depth > stack.length) {
                  // Deep enough for a nested list outright
                  //print ( "new nested list" );
                  list = make_list(m);
                  last_li.push(list);
                  last_li = list[1] = ["listitem"];
                } else {
                  // We aren't deep enough to be strictly a new level. This is
                  // where Md.pl goes nuts. If the indent matches a level in the
                  // stack, put it there, else put it one deeper then the
                  // wanted_depth deserves.
                  var found = false;
                  for (i = 0; i < stack.length; i++) {
                    if (stack[i].indent != m[1]) continue;
                    list = stack[i].list;
                    stack.splice(i + 1, stack.length - (i + 1));
                    found = true;
                    break;
                  }

                  if (!found) {
                    //print("not found. l:", uneval(l));
                    wanted_depth++;
                    if (wanted_depth <= stack.length) {
                      stack.splice(wanted_depth, stack.length - wanted_depth);
                      //print("Desired depth now", wanted_depth, "stack:", stack.length);
                      list = stack[wanted_depth - 1].list;
                      //print("list:", uneval(list) );
                    } else {
                      //print ("made new stack for messy indent");
                      list = make_list(m);
                      last_li.push(list);
                    }
                  }

                  //print( uneval(list), "last", list === stack[stack.length-1].list );
                  last_li = ["listitem"];
                  list.push(last_li);
                } // end depth of shenegains
                nl = "";
              }

              // Add content
              if (l.length > m[0].length) {
                li_accumulate += nl + l.substr(m[0].length);
              }
            } // tight_search

            if (li_accumulate.length) {
              add(last_li, loose, this.processInline(li_accumulate), nl);
              // Loose mode will have been dealt with. Reset it
              loose = false;
              li_accumulate = "";
            }

            // Look at the next block - we might have a loose list. Or an extra
            // paragraph for the current li
            var contained = get_contained_blocks(stack.length, next);

            // Deal with code blocks or properly nested lists
            if (contained.length > 0) {
              // Make sure all listitems up the stack are paragraphs
              forEach(stack, paragraphify, this);

              last_li.push.apply(last_li, this.toTree(contained, []));
            }

            var next_block = (next[0] && next[0].valueOf()) || "";

            if (next_block.match(is_list_re) || next_block.match(/^ /)) {
              block = next.shift();

              // Check for an HR following a list: features/lists/hr_abutting
              var hr = this.dialect.block.horizRule(block, next);

              if (hr) {
                ret.push.apply(ret, hr);
                break;
              }

              // Make sure all listitems up the stack are paragraphs
              forEach(stack, paragraphify, this);

              loose = true;
              continue loose_search;
            }
            break;
          } // loose_search

          return ret;
        };
      })(),

      blockquote: function blockquote(block, next) {
        if (!block.match(/^>/m)) return undefined;

        var jsonml = [];

        // separate out the leading abutting block, if any. I.e. in this case:
        //
        //  a
        //  > b
        //
        if (block[0] != ">") {
          var lines = block.split(/\n/),
            prev = [],
            line_no = block.lineNumber;

          // keep shifting lines until you find a crotchet
          while (lines.length && lines[0][0] != ">") {
            prev.push(lines.shift());
            line_no++;
          }

          var abutting = mk_block(prev.join("\n"), "\n", block.lineNumber);
          jsonml.push.apply(jsonml, this.processBlock(abutting, []));
          // reassemble new block of just block quotes!
          block = mk_block(lines.join("\n"), block.trailing, line_no);
        }

        // if the next block is also a blockquote merge it in
        while (next.length && next[0][0] == ">") {
          var b = next.shift();
          block = mk_block(block + block.trailing + b, b.trailing, block.lineNumber);
        }

        // Strip off the leading "> " and re-process as a block.
        var input = block.replace(/^> ?/gm, ""),
          old_tree = this.tree,
          processedBlock = this.toTree(input, ["blockquote"]),
          attr = extract_attr(processedBlock);

        // If any link references were found get rid of them
        if (attr && attr.references) {
          delete attr.references;
          // And then remove the attribute object if it's empty
          if (isEmpty(attr)) {
            processedBlock.splice(1, 1);
          }
        }

        jsonml.push(processedBlock);
        return jsonml;
      },

      referenceDefn: function referenceDefn(block, next) {
        var re = /^\s*\[(.*?)\]:\s*(\S+)(?:\s+(?:(['"])(.*?)\3|\((.*?)\)))?\n?/;
        // interesting matches are [ , ref_id, url, , title, title ]

        if (!block.match(re)) return undefined;

        // make an attribute node if it doesn't exist
        if (!extract_attr(this.tree)) {
          this.tree.splice(1, 0, {});
        }

        var attrs = extract_attr(this.tree);

        // make a references hash if it doesn't exist
        if (attrs.references === undefined) {
          attrs.references = {};
        }

        var b = this.loop_re_over_block(re, block, function (m) {
          if (m[2] && m[2][0] == "<" && m[2][m[2].length - 1] == ">") m[2] = m[2].substring(1, m[2].length - 1);

          var ref = (attrs.references[m[1].toLowerCase()] = {
            href: m[2],
          });

          if (m[4] !== undefined) ref.title = m[4];
          else if (m[5] !== undefined) ref.title = m[5];
        });

        if (b.length) next.unshift(mk_block(b, block.trailing));

        return [];
      },

      para: function para(block, next) {
        // everything's a para!
        return [["para"].concat(this.processInline(block))];
      },
    },
  };

  Markdown.dialects.Gruber.inline = {
    __oneElement__: function oneElement(text, patterns_or_re, previous_nodes) {
      var m,
        res,
        lastIndex = 0;

      patterns_or_re = patterns_or_re || this.dialect.inline.__patterns__;
      var re = new RegExp("([\\s\\S]*?)(" + (patterns_or_re.source || patterns_or_re) + ")");

      m = re.exec(text);
      if (!m) {
        // Just boring text
        return [text.length, text];
      } else if (m[1]) {
        // Some un-interesting text matched. Return that first
        return [m[1].length, m[1]];
      }

      var res;
      if (m[2] in this.dialect.inline) {
        res = this.dialect.inline[m[2]].call(this, text.substr(m.index), m, previous_nodes || []);
      }
      // Default for now to make dev easier. just slurp special and output it.
      res = res || [m[2].length, m[2]];
      return res;
    },

    __call__: function inline(text, patterns) {
      var out = [],
        res;

      function add(x) {
        //D:self.debug("  adding output", uneval(x));
        if (typeof x == "string" && typeof out[out.length - 1] == "string") out[out.length - 1] += x;
        else out.push(x);
      }

      while (text.length > 0) {
        res = this.dialect.inline.__oneElement__.call(this, text, patterns, out);
        text = text.substr(res.shift());
        forEach(res, add);
      }

      return out;
    },

    // These characters are intersting elsewhere, so have rules for them so that
    // chunks of plain text blocks don't include them
    "]": function () {},
    "}": function () {},

    __escape__: /^\\[\\`\*_{}\[\]()#\+.!\-]/,

    "\\": function escaped(text) {
      // [ length of input processed, node/children to add... ]
      // Only esacape: \ ` * _ { } [ ] ( ) # * + - . !
      if (this.dialect.inline.__escape__.exec(text)) return [2, text.charAt(1)];
      // Not an esacpe
      else return [1, "\\"];
    },

    "![": function image(text) {
      // Unlike images, alt text is plain text only. no other elements are
      // allowed in there

      // ![Alt text](/path/to/img.jpg "Optional title")
      //      1          2            3       4         <--- captures
      var m = text.match(/^!\[(.*?)\][ \t]*\([ \t]*([^")]*?)(?:[ \t]+(["'])(.*?)\3)?[ \t]*\)/);

      if (m) {
        if (m[2] && m[2][0] == "<" && m[2][m[2].length - 1] == ">") m[2] = m[2].substring(1, m[2].length - 1);

        m[2] = this.dialect.inline.__call__.call(this, m[2], /\\/)[0];

        var attrs = { alt: m[1], href: m[2] || "" };
        if (m[4] !== undefined) attrs.title = m[4];

        return [m[0].length, ["img", attrs]];
      }

      // ![Alt text][id]
      m = text.match(/^!\[(.*?)\][ \t]*\[(.*?)\]/);

      if (m) {
        // We can't check if the reference is known here as it likely wont be
        // found till after. Check it in md tree->hmtl tree conversion
        return [m[0].length, ["img_ref", { alt: m[1], ref: m[2].toLowerCase(), original: m[0] }]];
      }

      // Just consume the '!['
      return [2, "!["];
    },

    "[": function link(text) {
      var orig = String(text);
      // Inline content is possible inside `link text`
      var res = Markdown.DialectHelpers.inline_until_char.call(this, text.substr(1), "]");

      // No closing ']' found. Just consume the [
      if (!res) return [1, "["];

      var consumed = 1 + res[0],
        children = res[1],
        link,
        attrs;

      // At this point the first [...] has been parsed. See what follows to find
      // out which kind of link we are (reference or direct url)
      text = text.substr(consumed);

      // [link text](/path/to/img.jpg "Optional title")
      //                 1            2       3         <--- captures
      // This will capture up to the last paren in the block. We then pull
      // back based on if there a matching ones in the url
      //    ([here](/url/(test))
      // The parens have to be balanced
      var m = text.match(/^\s*\([ \t]*([^"']*)(?:[ \t]+(["'])(.*?)\2)?[ \t]*\)/);
      if (m) {
        var url = m[1];
        consumed += m[0].length;

        if (url && url[0] == "<" && url[url.length - 1] == ">") url = url.substring(1, url.length - 1);

        // If there is a title we don't have to worry about parens in the url
        if (!m[3]) {
          var open_parens = 1; // One open that isn't in the capture
          for (var len = 0; len < url.length; len++) {
            switch (url[len]) {
              case "(":
                open_parens++;
                break;
              case ")":
                if (--open_parens == 0) {
                  consumed -= url.length - len;
                  url = url.substring(0, len);
                }
                break;
            }
          }
        }

        // Process escapes only
        url = this.dialect.inline.__call__.call(this, url, /\\/)[0];

        attrs = { href: url || "" };
        if (m[3] !== undefined) attrs.title = m[3];

        link = ["link", attrs].concat(children);
        return [consumed, link];
      }

      // [Alt text][id]
      // [Alt text] [id]
      m = text.match(/^\s*\[(.*?)\]/);

      if (m) {
        consumed += m[0].length;

        // [links][] uses links as its reference
        attrs = { ref: (m[1] || String(children)).toLowerCase(), original: orig.substr(0, consumed) };

        link = ["link_ref", attrs].concat(children);

        // We can't check if the reference is known here as it likely wont be
        // found till after. Check it in md tree->hmtl tree conversion.
        // Store the original so that conversion can revert if the ref isn't found.
        return [consumed, link];
      }

      // [id]
      // Only if id is plain (no formatting.)
      if (children.length == 1 && typeof children[0] == "string") {
        attrs = { ref: children[0].toLowerCase(), original: orig.substr(0, consumed) };
        link = ["link_ref", attrs, children[0]];
        return [consumed, link];
      }

      // Just consume the "["
      return [1, "["];
    },

    "<": function autoLink(text) {
      var m;

      if ((m = text.match(/^<(?:((https?|ftp|mailto):[^>]+)|(.*?@.*?\.[a-zA-Z]+))>/)) != null) {
        if (m[3]) {
          return [m[0].length, ["link", { href: "mailto:" + m[3] }, m[3]]];
        } else if (m[2] == "mailto") {
          return [m[0].length, ["link", { href: m[1] }, m[1].substr("mailto:".length)]];
        } else return [m[0].length, ["link", { href: m[1] }, m[1]]];
      }

      return [1, "<"];
    },

    "`": function inlineCode(text) {
      // Inline code block. as many backticks as you like to start it
      // Always skip over the opening ticks.
      var m = text.match(/(`+)(([\s\S]*?)\1)/);

      if (m && m[2]) return [m[1].length + m[2].length, ["inlinecode", m[3]]];
      else {
        // TODO: No matching end code found - warn!
        return [1, "`"];
      }
    },

    "  \n": function lineBreak(text) {
      return [3, ["linebreak"]];
    },
  };

  // Meta Helper/generator method for em and strong handling
  function strong_em(tag, md) {
    var state_slot = tag + "_state",
      other_slot = tag == "strong" ? "em_state" : "strong_state";

    function CloseTag(len) {
      this.len_after = len;
      this.name = "close_" + md;
    }

    return function (text, orig_match) {
      if (this[state_slot][0] == md) {
        // Most recent em is of this type
        //D:this.debug("closing", md);
        this[state_slot].shift();

        // "Consume" everything to go back to the recrusion in the else-block below
        return [text.length, new CloseTag(text.length - md.length)];
      } else {
        // Store a clone of the em/strong states
        var other = this[other_slot].slice(),
          state = this[state_slot].slice();

        this[state_slot].unshift(md);

        //D:this.debug_indent += "  ";

        // Recurse
        var res = this.processInline(text.substr(md.length));
        //D:this.debug_indent = this.debug_indent.substr(2);

        var last = res[res.length - 1];

        //D:this.debug("processInline from", tag + ": ", uneval( res ) );

        var check = this[state_slot].shift();
        if (last instanceof CloseTag) {
          res.pop();
          // We matched! Huzzah.
          var consumed = text.length - last.len_after;
          return [consumed, [tag].concat(res)];
        } else {
          // Restore the state of the other kind. We might have mistakenly closed it.
          this[other_slot] = other;
          this[state_slot] = state;

          // We can't reuse the processed result as it could have wrong parsing contexts in it.
          return [md.length, md];
        }
      }
    }; // End returned function
  }

  Markdown.dialects.Gruber.inline["**"] = strong_em("strong", "**");
  Markdown.dialects.Gruber.inline["__"] = strong_em("strong", "__");
  Markdown.dialects.Gruber.inline["*"] = strong_em("em", "*");
  Markdown.dialects.Gruber.inline["_"] = strong_em("em", "_");

  // Build default order from insertion order.
  Markdown.buildBlockOrder = function (d) {
    var ord = [];
    for (var i in d) {
      if (i == "__order__" || i == "__call__") continue;
      ord.push(i);
    }
    d.__order__ = ord;
  };

  // Build patterns for inline matcher
  Markdown.buildInlinePatterns = function (d) {
    var patterns = [];

    for (var i in d) {
      // __foo__ is reserved and not a pattern
      if (i.match(/^__.*__$/)) continue;
      var l = i.replace(/([\\.*+?|()\[\]{}])/g, "\\$1").replace(/\n/, "\\n");
      patterns.push(i.length == 1 ? l : "(?:" + l + ")");
    }

    patterns = patterns.join("|");
    d.__patterns__ = patterns;
    //print("patterns:", uneval( patterns ) );

    var fn = d.__call__;
    d.__call__ = function (text, pattern) {
      if (pattern != undefined) {
        return fn.call(this, text, pattern);
      } else {
        return fn.call(this, text, patterns);
      }
    };
  };

  Markdown.DialectHelpers = {};
  Markdown.DialectHelpers.inline_until_char = function (text, want) {
    var consumed = 0,
      nodes = [];

    while (true) {
      if (text.charAt(consumed) == want) {
        // Found the character we were looking for
        consumed++;
        return [consumed, nodes];
      }

      if (consumed >= text.length) {
        // No closing char found. Abort.
        return null;
      }

      var res = this.dialect.inline.__oneElement__.call(this, text.substr(consumed));
      consumed += res[0];
      // Add any returned nodes.
      nodes.push.apply(nodes, res.slice(1));
    }
  };

  // Helper function to make sub-classing a dialect easier
  Markdown.subclassDialect = function (d) {
    function Block() {}
    Block.prototype = d.block;
    function Inline() {}
    Inline.prototype = d.inline;

    return { block: new Block(), inline: new Inline() };
  };

  Markdown.buildBlockOrder(Markdown.dialects.Gruber.block);
  Markdown.buildInlinePatterns(Markdown.dialects.Gruber.inline);

  Markdown.dialects.Maruku = Markdown.subclassDialect(Markdown.dialects.Gruber);

  Markdown.dialects.Maruku.processMetaHash = function processMetaHash(meta_string) {
    var meta = split_meta_hash(meta_string),
      attr = {};

    for (var i = 0; i < meta.length; ++i) {
      // id: #foo
      if (/^#/.test(meta[i])) {
        attr.id = meta[i].substring(1);
      }
      // class: .foo
      else if (/^\./.test(meta[i])) {
        // if class already exists, append the new one
        if (attr["class"]) {
          attr["class"] = attr["class"] + meta[i].replace(/./, " ");
        } else {
          attr["class"] = meta[i].substring(1);
        }
      }
      // attribute: foo=bar
      else if (/\=/.test(meta[i])) {
        var s = meta[i].split(/\=/);
        attr[s[0]] = s[1];
      }
    }

    return attr;
  };

  function split_meta_hash(meta_string) {
    var meta = meta_string.split(""),
      parts = [""],
      in_quotes = false;

    while (meta.length) {
      var letter = meta.shift();
      switch (letter) {
        case " ":
          // if we're in a quoted section, keep it
          if (in_quotes) {
            parts[parts.length - 1] += letter;
          }
          // otherwise make a new part
          else {
            parts.push("");
          }
          break;
        case "'":
        case '"':
          // reverse the quotes and move straight on
          in_quotes = !in_quotes;
          break;
        case "\\":
          // shift off the next letter to be used straight away.
          // it was escaped so we'll keep it whatever it is
          letter = meta.shift();
        default:
          parts[parts.length - 1] += letter;
          break;
      }
    }

    return parts;
  }

  Markdown.dialects.Maruku.block.document_meta = function document_meta(block, next) {
    // we're only interested in the first block
    if (block.lineNumber > 1) return undefined;

    // document_meta blocks consist of one or more lines of `Key: Value\n`
    if (!block.match(/^(?:\w+:.*\n)*\w+:.*$/)) return undefined;

    // make an attribute node if it doesn't exist
    if (!extract_attr(this.tree)) {
      this.tree.splice(1, 0, {});
    }

    var pairs = block.split(/\n/);
    for (p in pairs) {
      var m = pairs[p].match(/(\w+):\s*(.*)$/),
        key = m[1].toLowerCase(),
        value = m[2];

      this.tree[1][key] = value;
    }

    // document_meta produces no content!
    return [];
  };

  Markdown.dialects.Maruku.block.block_meta = function block_meta(block, next) {
    // check if the last line of the block is an meta hash
    var m = block.match(/(^|\n) {0,3}\{:\s*((?:\\\}|[^\}])*)\s*\}$/);
    if (!m) return undefined;

    // process the meta hash
    var attr = this.dialect.processMetaHash(m[2]);

    var hash;

    // if we matched ^ then we need to apply meta to the previous block
    if (m[1] === "") {
      var node = this.tree[this.tree.length - 1];
      hash = extract_attr(node);

      // if the node is a string (rather than JsonML), bail
      if (typeof node === "string") return undefined;

      // create the attribute hash if it doesn't exist
      if (!hash) {
        hash = {};
        node.splice(1, 0, hash);
      }

      // add the attributes in
      for (a in attr) {
        hash[a] = attr[a];
      }

      // return nothing so the meta hash is removed
      return [];
    }

    // pull the meta hash off the block and process what's left
    var b = block.replace(/\n.*$/, ""),
      result = this.processBlock(b, []);

    // get or make the attributes hash
    hash = extract_attr(result[0]);
    if (!hash) {
      hash = {};
      result[0].splice(1, 0, hash);
    }

    // attach the attributes to the block
    for (a in attr) {
      hash[a] = attr[a];
    }

    return result;
  };

  Markdown.dialects.Maruku.block.definition_list = function definition_list(block, next) {
    // one or more terms followed by one or more definitions, in a single block
    var tight = /^((?:[^\s:].*\n)+):\s+([\s\S]+)$/,
      list = ["dl"],
      i,
      m;

    // see if we're dealing with a tight or loose block
    if ((m = block.match(tight))) {
      // pull subsequent tight DL blocks out of `next`
      var blocks = [block];
      while (next.length && tight.exec(next[0])) {
        blocks.push(next.shift());
      }

      for (var b = 0; b < blocks.length; ++b) {
        var m = blocks[b].match(tight),
          terms = m[1].replace(/\n$/, "").split(/\n/),
          defns = m[2].split(/\n:\s+/);

        // print( uneval( m ) );

        for (i = 0; i < terms.length; ++i) {
          list.push(["dt", terms[i]]);
        }

        for (i = 0; i < defns.length; ++i) {
          // run inline processing over the definition
          list.push(["dd"].concat(this.processInline(defns[i].replace(/(\n)\s+/, "$1"))));
        }
      }
    } else {
      return undefined;
    }

    return [list];
  };

  // splits on unescaped instances of @ch. If @ch is not a character the result
  // can be unpredictable

  Markdown.dialects.Maruku.block.table = function table(block, next) {
    var _split_on_unescaped = function (s, ch) {
      ch = ch || "\\s";
      if (ch.match(/^[\\|\[\]{}?*.+^$]$/)) {
        ch = "\\" + ch;
      }
      var res = [],
        r = new RegExp("^((?:\\\\.|[^\\\\" + ch + "])*)" + ch + "(.*)"),
        m;
      while ((m = s.match(r))) {
        res.push(m[1]);
        s = m[2];
      }
      res.push(s);
      return res;
    };

    var leading_pipe = /^ {0,3}\|(.+)\n {0,3}\|\s*([\-:]+[\-| :]*)\n((?:\s*\|.*(?:\n|$))*)(?=\n|$)/,
      // find at least an unescaped pipe in each line
      no_leading_pipe =
        /^ {0,3}(\S(?:\\.|[^\\|])*\|.*)\n {0,3}([\-:]+\s*\|[\-| :]*)\n((?:(?:\\.|[^\\|])*\|.*(?:\n|$))*)(?=\n|$)/,
      i,
      m;
    if ((m = block.match(leading_pipe))) {
      // remove leading pipes in contents
      // (header and horizontal rule already have the leading pipe left out)
      m[3] = m[3].replace(/^\s*\|/gm, "");
    } else if (!(m = block.match(no_leading_pipe))) {
      return undefined;
    }

    var table = ["table", ["thead", ["tr"]], ["tbody"]];

    // remove trailing pipes, then split on pipes
    // (no escaped pipes are allowed in horizontal rule)
    m[2] = m[2].replace(/\|\s*$/, "").split("|");

    // process alignment
    var html_attrs = [];
    forEach(m[2], function (s) {
      if (s.match(/^\s*-+:\s*$/)) html_attrs.push({ align: "right" });
      else if (s.match(/^\s*:-+\s*$/)) html_attrs.push({ align: "left" });
      else if (s.match(/^\s*:-+:\s*$/)) html_attrs.push({ align: "center" });
      else html_attrs.push({});
    });

    // now for the header, avoid escaped pipes
    m[1] = _split_on_unescaped(m[1].replace(/\|\s*$/, ""), "|");
    for (i = 0; i < m[1].length; i++) {
      table[1][1].push(["th", html_attrs[i] || {}].concat(this.processInline(m[1][i].trim())));
    }

    // now for body contents
    forEach(
      m[3].replace(/\|\s*$/gm, "").split("\n"),
      function (row) {
        var html_row = ["tr"];
        row = _split_on_unescaped(row, "|");
        for (i = 0; i < row.length; i++) {
          html_row.push(["td", html_attrs[i] || {}].concat(this.processInline(row[i].trim())));
        }
        table[2].push(html_row);
      },
      this
    );

    return [table];
  };

  Markdown.dialects.Maruku.inline["{:"] = function inline_meta(text, matches, out) {
    if (!out.length) {
      return [2, "{:"];
    }

    // get the preceeding element
    var before = out[out.length - 1];

    if (typeof before === "string") {
      return [2, "{:"];
    }

    // match a meta hash
    var m = text.match(/^\{:\s*((?:\\\}|[^\}])*)\s*\}/);

    // no match, false alarm
    if (!m) {
      return [2, "{:"];
    }

    // attach the attributes to the preceeding element
    var meta = this.dialect.processMetaHash(m[1]),
      attr = extract_attr(before);

    if (!attr) {
      attr = {};
      before.splice(1, 0, attr);
    }

    for (var k in meta) {
      attr[k] = meta[k];
    }

    // cut out the string and replace it with nothing
    return [m[0].length, ""];
  };

  Markdown.dialects.Maruku.inline.__escape__ = /^\\[\\`\*_{}\[\]()#\+.!\-|:]/;

  Markdown.buildBlockOrder(Markdown.dialects.Maruku.block);
  Markdown.buildInlinePatterns(Markdown.dialects.Maruku.inline);

  var isArray =
    Array.isArray ||
    function (obj) {
      return Object.prototype.toString.call(obj) == "[object Array]";
    };

  var forEach;
  // Don't mess with Array.prototype. Its not friendly
  if (Array.prototype.forEach) {
    forEach = function (arr, cb, thisp) {
      return arr.forEach(cb, thisp);
    };
  } else {
    forEach = function (arr, cb, thisp) {
      for (var i = 0; i < arr.length; i++) {
        cb.call(thisp || arr, arr[i], i, arr);
      }
    };
  }

  var isEmpty = function (obj) {
    for (var key in obj) {
      if (hasOwnProperty.call(obj, key)) {
        return false;
      }
    }

    return true;
  };

  function extract_attr(jsonml) {
    return isArray(jsonml) && jsonml.length > 1 && typeof jsonml[1] === "object" && !isArray(jsonml[1])
      ? jsonml[1]
      : undefined;
  }

  /**
   *  renderJsonML( jsonml[, options] ) -> String
   *  - jsonml (Array): JsonML array to render to XML
   *  - options (Object): options
   *
   *  Converts the given JsonML into well-formed XML.
   *
   *  The options currently understood are:
   *
   *  - root (Boolean): wether or not the root node should be included in the
   *    output, or just its children. The default `false` is to not include the
   *    root itself.
   */
  expose.renderJsonML = function (jsonml, options) {
    options = options || {};
    // include the root element in the rendered output?
    options.root = options.root || false;

    var content = [];

    if (options.root) {
      content.push(render_tree(jsonml));
    } else {
      jsonml.shift(); // get rid of the tag
      if (jsonml.length && typeof jsonml[0] === "object" && !(jsonml[0] instanceof Array)) {
        jsonml.shift(); // get rid of the attributes
      }

      while (jsonml.length) {
        content.push(render_tree(jsonml.shift()));
      }
    }

    return content.join("\n\n");
  };

  function escapeHTML(text) {
    return text
      .replace(/&/g, "&amp;")
      .replace(/</g, "&lt;")
      .replace(/>/g, "&gt;")
      .replace(/"/g, "&quot;")
      .replace(/'/g, "&#39;");
  }

  function render_tree(jsonml) {
    // basic case
    if (typeof jsonml === "string") {
      return escapeHTML(jsonml);
    }

    var tag = jsonml.shift(),
      attributes = {},
      content = [];

    if (jsonml.length && typeof jsonml[0] === "object" && !(jsonml[0] instanceof Array)) {
      attributes = jsonml.shift();
    }

    while (jsonml.length) {
      content.push(render_tree(jsonml.shift()));
    }

    var tag_attrs = "";
    for (var a in attributes) {
      tag_attrs += " " + a + '="' + escapeHTML(attributes[a]) + '"';
    }

    // be careful about adding whitespace here for inline elements
    if (tag == "img" || tag == "br" || tag == "hr") {
      return "<" + tag + tag_attrs + "/>";
    } else {
      return "<" + tag + tag_attrs + ">" + content.join("") + "</" + tag + ">";
    }
  }

  function convert_tree_to_html(tree, references, options) {
    var i;
    options = options || {};

    // shallow clone
    var jsonml = tree.slice(0);

    if (typeof options.preprocessTreeNode === "function") {
      jsonml = options.preprocessTreeNode(jsonml, references);
    }

    // Clone attributes if they exist
    var attrs = extract_attr(jsonml);
    if (attrs) {
      jsonml[1] = {};
      for (i in attrs) {
        jsonml[1][i] = attrs[i];
      }
      attrs = jsonml[1];
    }

    // basic case
    if (typeof jsonml === "string") {
      return jsonml;
    }

    // convert this node
    switch (jsonml[0]) {
      case "header":
        jsonml[0] = "h" + jsonml[1].level;
        delete jsonml[1].level;
        break;
      case "bulletlist":
        jsonml[0] = "ul";
        break;
      case "numberlist":
        jsonml[0] = "ol";
        break;
      case "listitem":
        jsonml[0] = "li";
        break;
      case "para":
        jsonml[0] = "p";
        break;
      case "markdown":
        jsonml[0] = "html";
        if (attrs) delete attrs.references;
        break;
      case "code_block":
        jsonml[0] = "pre";
        i = attrs ? 2 : 1;
        var code = ["code"];
        code.push.apply(code, jsonml.splice(i, jsonml.length - i));
        jsonml[i] = code;
        break;
      case "inlinecode":
        jsonml[0] = "code";
        break;
      case "img":
        jsonml[1].src = jsonml[1].href;
        delete jsonml[1].href;
        break;
      case "linebreak":
        jsonml[0] = "br";
        break;
      case "link":
        jsonml[0] = "a";
        break;
      case "link_ref":
        jsonml[0] = "a";

        // grab this ref and clean up the attribute node
        var ref = references[attrs.ref];

        // if the reference exists, make the link
        if (ref) {
          delete attrs.ref;

          // add in the href and title, if present
          attrs.href = ref.href;
          if (ref.title) {
            attrs.title = ref.title;
          }

          // get rid of the unneeded original text
          delete attrs.original;
        }
        // the reference doesn't exist, so revert to plain text
        else {
          return attrs.original;
        }
        break;
      case "img_ref":
        jsonml[0] = "img";

        // grab this ref and clean up the attribute node
        var ref = references[attrs.ref];

        // if the reference exists, make the link
        if (ref) {
          delete attrs.ref;

          // add in the href and title, if present
          attrs.src = ref.href;
          if (ref.title) {
            attrs.title = ref.title;
          }

          // get rid of the unneeded original text
          delete attrs.original;
        }
        // the reference doesn't exist, so revert to plain text
        else {
          return attrs.original;
        }
        break;
    }

    // convert all the children
    i = 1;

    // deal with the attribute node, if it exists
    if (attrs) {
      // if there are keys, skip over it
      for (var key in jsonml[1]) {
        i = 2;
        break;
      }
      // if there aren't, remove it
      if (i === 1) {
        jsonml.splice(i, 1);
      }
    }

    for (; i < jsonml.length; ++i) {
      jsonml[i] = convert_tree_to_html(jsonml[i], references, options);
    }

    return jsonml;
  }

  // merges adjacent text nodes into a single node
  function merge_text_nodes(jsonml) {
    // skip the tag name and attribute hash
    var i = extract_attr(jsonml) ? 2 : 1;

    while (i < jsonml.length) {
      // if it's a string check the next item too
      if (typeof jsonml[i] === "string") {
        if (i + 1 < jsonml.length && typeof jsonml[i + 1] === "string") {
          // merge the second string into the first and remove it
          jsonml[i] += jsonml.splice(i + 1, 1)[0];
        } else {
          ++i;
        }
      }
      // if it's not a string recurse
      else {
        merge_text_nodes(jsonml[i]);
        ++i;
      }
    }
  }
})(
  (function () {
    if (typeof exports === "undefined") {
      window.markdown = {};
      return window.markdown;
    } else {
      return exports;
    }
  })()
);
export default expose;
